forked from moby/moby
/
image_builder.go
632 lines (544 loc) · 18.7 KB
/
image_builder.go
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package containerd
import (
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"os"
"runtime"
"time"
containerd "github.com/containerd/containerd/v2/client"
"github.com/containerd/containerd/v2/core/content"
containerdimages "github.com/containerd/containerd/v2/core/images"
"github.com/containerd/containerd/v2/core/leases"
"github.com/containerd/containerd/v2/core/mount"
"github.com/containerd/containerd/v2/pkg/rootfs"
cerrdefs "github.com/containerd/errdefs"
"github.com/containerd/log"
"github.com/containerd/platforms"
"github.com/distribution/reference"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/api/types/registry"
"github.com/docker/docker/builder"
"github.com/docker/docker/errdefs"
dimage "github.com/docker/docker/image"
"github.com/docker/docker/internal/compatcontext"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/progress"
"github.com/docker/docker/pkg/streamformatter"
"github.com/docker/docker/pkg/stringid"
registrypkg "github.com/docker/docker/registry"
imagespec "github.com/moby/docker-image-spec/specs-go/v1"
"github.com/opencontainers/go-digest"
"github.com/opencontainers/image-spec/identity"
"github.com/opencontainers/image-spec/specs-go"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
const (
// Digest of the image which was the base image of the committed container.
imageLabelClassicBuilderParent = "org.mobyproject.image.parent"
// "1" means that the image was created directly from the "FROM scratch".
imageLabelClassicBuilderFromScratch = "org.mobyproject.image.fromscratch"
// digest of the ContainerConfig stored in the content store.
imageLabelClassicBuilderContainerConfig = "org.mobyproject.image.containerconfig"
)
const (
// gc.ref label that associates the ContainerConfig content blob with the
// corresponding Config content.
contentLabelGcRefContainerConfig = "containerd.io/gc.ref.content.moby/container.config"
// Digest of the image this ContainerConfig blobs describes.
// Only ContainerConfig content should be labelled with it.
contentLabelClassicBuilderImage = "org.mobyproject.content.image"
)
// GetImageAndReleasableLayer returns an image and releaseable layer for a
// reference or ID. Every call to GetImageAndReleasableLayer MUST call
// releasableLayer.Release() to prevent leaking of layers.
func (i *ImageService) GetImageAndReleasableLayer(ctx context.Context, refOrID string, opts backend.GetImageAndLayerOptions) (builder.Image, builder.ROLayer, error) {
if refOrID == "" { // FROM scratch
if runtime.GOOS == "windows" {
return nil, nil, fmt.Errorf(`"FROM scratch" is not supported on Windows`)
}
if opts.Platform != nil {
if err := dimage.CheckOS(opts.Platform.OS); err != nil {
return nil, nil, err
}
}
return nil, &rolayer{
c: i.client,
snapshotter: i.snapshotter,
}, nil
}
if opts.PullOption != backend.PullOptionForcePull {
// TODO(laurazard): same as below
img, err := i.GetImage(ctx, refOrID, backend.GetImageOpts{Platform: opts.Platform})
if err != nil && opts.PullOption == backend.PullOptionNoPull {
return nil, nil, err
}
imgDesc, err := i.resolveDescriptor(ctx, refOrID)
if err != nil && !errdefs.IsNotFound(err) {
return nil, nil, err
}
if img != nil {
if err := dimage.CheckOS(img.OperatingSystem()); err != nil {
return nil, nil, err
}
roLayer, err := newROLayerForImage(ctx, &imgDesc, i, opts.Platform)
if err != nil {
return nil, nil, err
}
return img, roLayer, nil
}
}
ctx, _, err := i.client.WithLease(ctx, leases.WithRandomID(), leases.WithExpiration(1*time.Hour))
if err != nil {
return nil, nil, fmt.Errorf("failed to create lease for commit: %w", err)
}
// TODO(laurazard): do we really need a new method here to pull the image?
imgDesc, err := i.pullForBuilder(ctx, refOrID, opts.AuthConfig, opts.Output, opts.Platform)
if err != nil {
return nil, nil, err
}
// TODO(laurazard): pullForBuilder should return whatever we
// need here instead of having to go and get it again
img, err := i.GetImage(ctx, refOrID, backend.GetImageOpts{
Platform: opts.Platform,
})
if err != nil {
return nil, nil, err
}
roLayer, err := newROLayerForImage(ctx, imgDesc, i, opts.Platform)
if err != nil {
return nil, nil, err
}
return img, roLayer, nil
}
func (i *ImageService) pullForBuilder(ctx context.Context, name string, authConfigs map[string]registry.AuthConfig, output io.Writer, platform *ocispec.Platform) (*ocispec.Descriptor, error) {
ref, err := reference.ParseNormalizedNamed(name)
if err != nil {
return nil, err
}
pullRegistryAuth := ®istry.AuthConfig{}
if len(authConfigs) > 0 {
// The request came with a full auth config, use it
repoInfo, err := i.registryService.ResolveRepository(ref)
if err != nil {
return nil, err
}
resolvedConfig := registrypkg.ResolveAuthConfig(authConfigs, repoInfo.Index)
pullRegistryAuth = &resolvedConfig
}
if err := i.PullImage(ctx, reference.TagNameOnly(ref), platform, nil, pullRegistryAuth, output); err != nil {
return nil, err
}
img, err := i.GetImage(ctx, name, backend.GetImageOpts{Platform: platform})
if err != nil {
if errdefs.IsNotFound(err) && img != nil && platform != nil {
imgPlat := ocispec.Platform{
OS: img.OS,
Architecture: img.BaseImgArch(),
Variant: img.BaseImgVariant(),
}
p := *platform
if !platforms.Only(p).Match(imgPlat) {
po := streamformatter.NewJSONProgressOutput(output, false)
progress.Messagef(po, "", `
WARNING: Pulled image with specified platform (%s), but the resulting image's configured platform (%s) does not match.
This is most likely caused by a bug in the build system that created the fetched image (%s).
Please notify the image author to correct the configuration.`,
platforms.Format(p), platforms.Format(imgPlat), name,
)
log.G(ctx).WithError(err).WithField("image", name).Warn("Ignoring error about platform mismatch where the manifest list points to an image whose configuration does not match the platform in the manifest.")
}
} else {
return nil, err
}
}
if err := dimage.CheckOS(img.OperatingSystem()); err != nil {
return nil, err
}
imgDesc, err := i.resolveDescriptor(ctx, name)
if err != nil {
return nil, err
}
return &imgDesc, err
}
func newROLayerForImage(ctx context.Context, imgDesc *ocispec.Descriptor, i *ImageService, platform *ocispec.Platform) (builder.ROLayer, error) {
if imgDesc == nil {
return nil, fmt.Errorf("can't make an RO layer for a nil image :'(")
}
platMatcher := platforms.Default()
if platform != nil {
platMatcher = platforms.Only(*platform)
}
confDesc, err := containerdimages.Config(ctx, i.client.ContentStore(), *imgDesc, platMatcher)
if err != nil {
return nil, err
}
diffIDs, err := containerdimages.RootFS(ctx, i.client.ContentStore(), confDesc)
if err != nil {
return nil, err
}
// TODO(vvoland): Check if image is unpacked, and unpack it if it's not.
imageSnapshotID := identity.ChainID(diffIDs).String()
snapshotter := i.StorageDriver()
_, lease, err := createLease(ctx, i.client.LeasesService())
if err != nil {
return nil, errdefs.System(fmt.Errorf("failed to lease image snapshot %s: %w", imageSnapshotID, err))
}
return &rolayer{
key: imageSnapshotID,
c: i.client,
snapshotter: snapshotter,
diffID: "", // Image RO layer doesn't have a diff.
contentStoreDigest: "",
lease: &lease,
}, nil
}
func createLease(ctx context.Context, lm leases.Manager) (context.Context, leases.Lease, error) {
lease, err := lm.Create(ctx,
leases.WithExpiration(time.Hour*24),
leases.WithLabels(map[string]string{
"org.mobyproject.lease.classicbuilder": "true",
}),
)
if err != nil {
return nil, leases.Lease{}, fmt.Errorf("failed to create a lease for snapshot: %w", err)
}
return leases.WithLease(ctx, lease.ID), lease, nil
}
type rolayer struct {
key string
c *containerd.Client
snapshotter string
diffID layer.DiffID
contentStoreDigest digest.Digest
lease *leases.Lease
}
func (rl *rolayer) ContentStoreDigest() digest.Digest {
return rl.contentStoreDigest
}
func (rl *rolayer) DiffID() layer.DiffID {
if rl.diffID == "" {
return layer.DigestSHA256EmptyTar
}
return rl.diffID
}
func (rl *rolayer) Release() error {
if rl.lease != nil {
lm := rl.c.LeasesService()
err := lm.Delete(context.TODO(), *rl.lease)
if err != nil {
return err
}
rl.lease = nil
}
return nil
}
// NewRWLayer creates a new read-write layer for the builder
func (rl *rolayer) NewRWLayer() (_ builder.RWLayer, outErr error) {
snapshotter := rl.c.SnapshotService(rl.snapshotter)
key := stringid.GenerateRandomID()
ctx, lease, err := createLease(context.TODO(), rl.c.LeasesService())
if err != nil {
return nil, err
}
defer func() {
if outErr != nil {
if err := rl.c.LeasesService().Delete(ctx, lease); err != nil {
log.G(ctx).WithError(err).Warn("failed to remove lease after NewRWLayer error")
}
}
}()
mounts, err := snapshotter.Prepare(ctx, key, rl.key)
if err != nil {
return nil, err
}
root, err := os.MkdirTemp(os.TempDir(), "rootfs-mount")
if err != nil {
return nil, err
}
if err := mount.All(mounts, root); err != nil {
return nil, err
}
return &rwlayer{
key: key,
parent: rl.key,
c: rl.c,
snapshotter: rl.snapshotter,
root: root,
lease: &lease,
}, nil
}
type rwlayer struct {
key string
parent string
c *containerd.Client
snapshotter string
root string
lease *leases.Lease
}
func (rw *rwlayer) Root() string {
return rw.root
}
func (rw *rwlayer) Commit() (_ builder.ROLayer, outErr error) {
snapshotter := rw.c.SnapshotService(rw.snapshotter)
key := stringid.GenerateRandomID()
lm := rw.c.LeasesService()
ctx, lease, err := createLease(context.TODO(), lm)
if err != nil {
return nil, err
}
defer func() {
if outErr != nil {
if err := lm.Delete(ctx, lease); err != nil {
log.G(ctx).WithError(err).Warn("failed to remove lease after NewRWLayer error")
}
}
}()
// Unmount the layer, required by the containerd windows snapshotter.
// The windowsfilter graphdriver does this inside its own Diff method.
//
// The only place that calls this in-tree is (b *Builder) exportImage and
// that is called from the end of (b *Builder) performCopy which has a
// `defer rwLayer.Release()` pending.
//
// After the snapshotter.Commit the source snapshot is deleted anyway and
// it shouldn't be accessed afterwards.
if rw.root != "" {
if err := mount.UnmountAll(rw.root, 0); err != nil && !errors.Is(err, os.ErrNotExist) {
log.G(ctx).WithError(err).WithField("root", rw.root).Error("failed to unmount RWLayer")
return nil, err
}
}
err = snapshotter.Commit(ctx, key, rw.key)
if err != nil && !cerrdefs.IsAlreadyExists(err) {
return nil, err
}
differ := rw.c.DiffService()
desc, err := rootfs.CreateDiff(ctx, key, snapshotter, differ)
if err != nil {
return nil, err
}
info, err := rw.c.ContentStore().Info(ctx, desc.Digest)
if err != nil {
return nil, err
}
diffIDStr, ok := info.Labels["containerd.io/uncompressed"]
if !ok {
return nil, fmt.Errorf("invalid differ response with no diffID")
}
diffID, err := digest.Parse(diffIDStr)
if err != nil {
return nil, err
}
return &rolayer{
key: key,
c: rw.c,
snapshotter: rw.snapshotter,
diffID: layer.DiffID(diffID),
contentStoreDigest: desc.Digest,
lease: &lease,
}, nil
}
func (rw *rwlayer) Release() (outErr error) {
if rw.root == "" { // nothing to release
return nil
}
if err := mount.UnmountAll(rw.root, 0); err != nil && !errors.Is(err, os.ErrNotExist) {
log.G(context.TODO()).WithError(err).WithField("root", rw.root).Error("failed to unmount RWLayer")
return err
}
if err := os.Remove(rw.root); err != nil && !errors.Is(err, os.ErrNotExist) {
log.G(context.TODO()).WithError(err).WithField("dir", rw.root).Error("failed to remove mount temp dir")
return err
}
rw.root = ""
if rw.lease != nil {
lm := rw.c.LeasesService()
err := lm.Delete(context.TODO(), *rw.lease)
if err != nil {
log.G(context.TODO()).WithError(err).Warn("failed to delete lease when releasing RWLayer")
} else {
rw.lease = nil
}
}
return nil
}
// CreateImage creates a new image by adding a config and ID to the image store.
// This is similar to LoadImage() except that it receives JSON encoded bytes of
// an image instead of a tar archive.
func (i *ImageService) CreateImage(ctx context.Context, config []byte, parent string, layerDigest digest.Digest) (builder.Image, error) {
imgToCreate, err := dimage.NewFromJSON(config)
if err != nil {
return nil, err
}
ociImgToCreate := dockerImageToDockerOCIImage(*imgToCreate)
var layers []ocispec.Descriptor
var parentDigest digest.Digest
// if the image has a parent, we need to start with the parents layers descriptors
if parent != "" {
parentDesc, err := i.resolveDescriptor(ctx, parent)
if err != nil {
return nil, err
}
parentImageManifest, err := containerdimages.Manifest(ctx, i.client.ContentStore(), parentDesc, platforms.Default())
if err != nil {
return nil, err
}
layers = parentImageManifest.Layers
parentDigest = parentDesc.Digest
}
cs := i.client.ContentStore()
ra, err := cs.ReaderAt(ctx, ocispec.Descriptor{Digest: layerDigest})
if err != nil {
return nil, fmt.Errorf("failed to read diff archive: %w", err)
}
defer ra.Close()
empty, err := archive.IsEmpty(content.NewReader(ra))
if err != nil {
return nil, fmt.Errorf("failed to check if archive is empty: %w", err)
}
if !empty {
info, err := cs.Info(ctx, layerDigest)
if err != nil {
return nil, err
}
layers = append(layers, ocispec.Descriptor{
MediaType: containerdimages.MediaTypeDockerSchema2LayerGzip,
Digest: layerDigest,
Size: info.Size,
})
}
createdImageId, err := i.createImageOCI(ctx, ociImgToCreate, parentDigest, layers, imgToCreate.ContainerConfig)
if err != nil {
return nil, err
}
return dimage.Clone(imgToCreate, createdImageId), nil
}
func (i *ImageService) createImageOCI(ctx context.Context, imgToCreate imagespec.DockerOCIImage,
parentDigest digest.Digest, layers []ocispec.Descriptor,
containerConfig container.Config,
) (dimage.ID, error) {
// Necessary to prevent the contents from being GC'd
// between writing them here and creating an image
ctx, release, err := i.client.WithLease(ctx, leases.WithRandomID(), leases.WithExpiration(1*time.Hour))
if err != nil {
return "", err
}
defer func() {
if err := release(compatcontext.WithoutCancel(ctx)); err != nil {
log.G(ctx).WithError(err).Warn("failed to release lease created for create")
}
}()
manifestDesc, ccDesc, err := writeContentsForImage(ctx, i.snapshotter, i.client.ContentStore(), imgToCreate, layers, containerConfig)
if err != nil {
return "", err
}
img := containerdimages.Image{
Name: danglingImageName(manifestDesc.Digest),
Target: manifestDesc,
CreatedAt: time.Now(),
Labels: map[string]string{
imageLabelClassicBuilderParent: parentDigest.String(),
imageLabelClassicBuilderContainerConfig: ccDesc.Digest.String(),
},
}
if parentDigest == "" {
img.Labels[imageLabelClassicBuilderFromScratch] = "1"
}
createdImage, err := i.client.ImageService().Update(ctx, img)
if err != nil {
if !cerrdefs.IsNotFound(err) {
return "", err
}
if createdImage, err = i.client.ImageService().Create(ctx, img); err != nil {
return "", fmt.Errorf("failed to create new image: %w", err)
}
}
if err := i.unpackImage(ctx, i.StorageDriver(), img, manifestDesc); err != nil {
return "", err
}
return dimage.ID(createdImage.Target.Digest), nil
}
// writeContentsForImage will commit oci image config and manifest into containerd's content store.
func writeContentsForImage(ctx context.Context, snName string, cs content.Store,
newConfig imagespec.DockerOCIImage, layers []ocispec.Descriptor,
containerConfig container.Config,
) (
manifestDesc ocispec.Descriptor,
containerConfigDesc ocispec.Descriptor,
_ error,
) {
newConfigJSON, err := json.Marshal(newConfig)
if err != nil {
return ocispec.Descriptor{}, ocispec.Descriptor{}, err
}
configDesc := ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageConfig,
Digest: digest.FromBytes(newConfigJSON),
Size: int64(len(newConfigJSON)),
}
newMfst := struct {
MediaType string `json:"mediaType,omitempty"`
ocispec.Manifest
}{
MediaType: ocispec.MediaTypeImageManifest,
Manifest: ocispec.Manifest{
Versioned: specs.Versioned{
SchemaVersion: 2,
},
Config: configDesc,
Layers: layers,
},
}
newMfstJSON, err := json.MarshalIndent(newMfst, "", " ")
if err != nil {
return ocispec.Descriptor{}, ocispec.Descriptor{}, err
}
newMfstDesc := ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageManifest,
Digest: digest.FromBytes(newMfstJSON),
Size: int64(len(newMfstJSON)),
}
// new manifest should reference the layers and config content
labels := map[string]string{
"containerd.io/gc.ref.content.0": configDesc.Digest.String(),
}
for i, l := range layers {
labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i+1)] = l.Digest.String()
}
err = content.WriteBlob(ctx, cs, newMfstDesc.Digest.String(), bytes.NewReader(newMfstJSON), newMfstDesc, content.WithLabels(labels))
if err != nil {
return ocispec.Descriptor{}, ocispec.Descriptor{}, err
}
ccDesc, err := saveContainerConfig(ctx, cs, newMfstDesc.Digest, containerConfig)
if err != nil {
return ocispec.Descriptor{}, ocispec.Descriptor{}, err
}
// config should reference to snapshotter and container config
labelOpt := content.WithLabels(map[string]string{
fmt.Sprintf("containerd.io/gc.ref.snapshot.%s", snName): identity.ChainID(newConfig.RootFS.DiffIDs).String(),
contentLabelGcRefContainerConfig: ccDesc.Digest.String(),
})
err = content.WriteBlob(ctx, cs, configDesc.Digest.String(), bytes.NewReader(newConfigJSON), configDesc, labelOpt)
if err != nil {
return ocispec.Descriptor{}, ocispec.Descriptor{}, err
}
return newMfstDesc, ccDesc, nil
}
// saveContainerConfig serializes the given ContainerConfig into a json and
// stores it in the content store and returns its descriptor.
func saveContainerConfig(ctx context.Context, content content.Ingester, imgID digest.Digest, containerConfig container.Config) (ocispec.Descriptor, error) {
containerConfigDesc, err := storeJson(ctx, content,
"application/vnd.docker.container.image.v1+json", containerConfig,
map[string]string{contentLabelClassicBuilderImage: imgID.String()},
)
if err != nil {
return ocispec.Descriptor{}, err
}
return containerConfigDesc, nil
}